The present invention relates generally to optical communications, and more particularly, to a POLMUX-OFDM-DD transmitter and receiver architecture for reduced complexity and overhead in Optical Access/Metro Transmission.
Polarization multiplexed (POLMUX) orthogonal frequency-division multiplexing (OFDM) transmission with direct detection (DD), abbreviated as POLMUX-OFDM-DD, has been shown to be a powerful technology which can achieve 40-100 Gb/s per wavelength transmission in next-generation optical access/metro networks. New transmitter and receiver side digital signal processing (DSP) algorithms have also been proposed to reduce implementation complexity in the electronic domain. However, novel transmitter and receiver side architectures that reduce optical component complexity have not yet been addressed. Moreover, new training sequence designs to reduce the training signal based overhead in these systems have likewise not been addressed.
In previous proposals, transmitter-side optical architectures have exploited advanced optical components such as multiple optical interleavers (ILs) to generate an optical single sideband POLMUX-OFDM signal and realize single-wavelength downstream transmission. For optical access/metro networks, this can be a costly transmitter side requirement.
On the receiver side, previous proposals have exploited optical filtering to reduce post-photodetection electronic DSP requirements. However, in so doing, the previous architectures can only work correctly for a limited set of incoming POLMUX-OFDM signal polarization states, which greatly limits their practical applicability in real systems where the incoming polarization can be completely random.
In terms of training sequence overhead, to the best of our knowledge, no new designs that reduce the high training-sequence based overhead have been proposed. This is an important problem because training sequences are the key requirement for receiver-side channel estimation which enables cross MCS.
Accordingly, there is a need for an improved POLMUX-OFDM-DD transmitter and receiver architecture for reduced complexity and overhead in Optical Access/Metro Transmission.